PREV MED PEARLS Flashcards
Aprropriate measure of central tendency in qualitative data such as gender, religion or nationality
MODE
Average; sum of observations divided by the number of observations
MEAN
Middle observation in a series of ordered observations eg. 50th percentile
MEDIAN
Observation that occurs with the greatest frequency
MODE
Branch of medicine that deals with study of causes, distribution and control of disease in populations
EPIDEMIOLOGY
Distribution and determination of frequency of disease in humans
EPIDEMIOLOGY
Samplin unit in epidemiologic studies in the identification of causal factors
GROUP of INDIVIDUALS
Ultimate goal of an epidemiologic investigation
INSTITUTE CURATIVE, PREVENTIVE and CONTROL MEASURES to AVOID MORE CASES
Studies both the DISTRIBUTION OF DISEASES in human populations and the DETERMINANTS OF THE OBSERVED DISTRIBUTION; began as study of infectious diseases; expanded to include the study of Chronic Disease, Organization of Health Care, Delivery of Health Care and Occupational and Environmental Health
EPIDEMIOLOGY
Study of distribution of diseases in animals
EPIZOOTIOLOGY
SLOW and PROGRESSIVE CHANGE in the antigenic composition of microorganisms; alters the immunological responses of individuals and a populations susceptibility to that microorganism
ANTIGENIC DRIFT
SUDDEN CHANGE in the molecular structure of a microorganism and produces new strain; results in little or no acquired immunity to these new strains and is the explanation for new epidemics or pandemics
ANTIGENIC SHIFT
Result in influenza cases with high case fatality rates seen previously with this strain
VACCINE FAILURE
Decrease the probability that a susceptible person would come into contact with an infected person; would not affect the clinical presentation of those infected
HERD IMMUNITY
No cases on record,disease absent from beginning, disease has been eradicated
ABSENCE OF DISEASE
Occurrence of few and unrelated cases
SPORADIC
Constant occurrence
ENDEMIC
Occurrence of a number of cases of disease in excess of normal occurrence of expectancy
EPIDEMIC
Epidemic involving many countries
PANDEMIC
Association between Low Birth Weight and Maternal Smoking during pregnancy studies by obtaining smoking histories from women at the time of the prenatal visit and subsequently correlated birth weight with smoking histories
PROSPECTIVE COHORT
Large number of persons have acquired mild symptoms of a disease despite being vaccinated for the appropriate strain being cultured and finding out it’s the same as that incorporated into the trivalent vaccine administered throughout the world, also noting that the strain had high case fatality rate in previous epidemics in China, where most new strains are isolated and identified for vaccine preparations
ANTIGENIC DRIFT
Recommended study for finding out the cause of a rare form of a disease, with access to the largest database of cases about the disease but there is scarcity of time and resources
CASE CONTROL
In finding out the cause of lung cancer, patients who had the disease are matched with controls by age, sex, place of residence, and social class then the frequency of cigarette smoking are compared in the 2 groups
CASE CONTROL
A research team wishes to investigate a possible association between smokeless tobacco and oral lesions among professional baseball players, they ask each player about current and past use of smokeless tobacco, cigarettes and alcohol then a dentist notes the type and extent of lesions in the mouth
CROSS SECTIONAL
Subjects are categorized on the basis of exposure or lack of exposure to a risk factor, then are followed to determine if a particular outcome develops
PROSPECTIVE COHORT
Groups of subjects who are followed forward in time to see which ones develop the outcome
COHORT
Prospective studies in which an intervention is applied
CLINICAL TRIALS
study of the relationship between low birth weights and maternal smoking, infants are selected on the basis of low birth weight and normal birth weight and then the frequency of maternal smoking would be compared in the two groups
RETROSPECTIVE CASE CONTROL
Exposure and outcome are measure at the same point in time
CROSS SECTIONAL
Clinical characteristic or outcome from a SINGLE clinical subject or event (n=1); No control; Eg. A 23 yr old man with MDRTB
CASE REPORT
Clinical characteristic or outcome from a GROUP of clinical subjects or events (n>1); No controls; Eg. Patients in a local hospital with MDRTB
CASE SERIES
PREVALENCE STUDY; determines in each member of the population the PRESENCE OR ABSENCE OF A DISEASE and other variables AT ONE POINT IN TIME; assesses the association of risk factor and disease; CAUSALITY CANNOT USUALLY BE DETERMINED; No controls; Eg. Who in the community NOW has MDRTB?
CROSS SECTIONAL
Identifies a group of people with the disease (CASE) and compares them with a suitable comparison group without the disease (CONTROL); retrospective; assesses many risk factors for disease; can help determine causal relationships; weakest because outcome has already happened; cannot assess incidence and prevalence of disease; VERY USEFUL FOR STUDYING CONDITIONS WITH VERY LOW INCIDENCE OR PREVALENCE; Cases vs Controls; Eg. Comparing cases of MDRTB with cases of nonresistant TB
CASE CONTROL
Population group exposed to a risk factor is followed over time compared with a group not exposed to the risk factors; outcome is disease incidence in each group; prospective; can determine incidence and causal relationships if there is statistical association between risk factor and disease; Population at risk vs Population not at risk; Eg. Following a prison inmate population and marking the development of MDRTB
COHORT
Notification of health providers concerning increased cases, education of the public concerning self- protective measures, control of the snail host, Oncomelania quadrasi
PUBLIC HEALTH POLICIES for PREVENTION and CONTROL
Methods used are public education, surveillance systems, environmental control and dissemination of information to health providers; Individual treatment is traditionally left to individual practitioners
PUBLIC HEALTH
Number of true positives divided by number of all people with disease; Positive In Disease; used to RULE OUT a disease; high factor is desirable for a Screening test, to rule out
SENSITIVITY
Number of true negatives divided by the number of all people without the disease; Negative In Health; used to RULE IN; high factor is desirable for a Confirmatory test, to rule in
SPECIFICITY
Total number of cases in a population at a given time
PREVALENCE
Number of new cases in a population per unit time; NEW cases
INCIDENCE
Number of true positives divided by the number of people who tested positive for the disease; probability of having a condition, given a positive test
POSITIVE PREDICTIVE VALUE
Number of true negatives divided by the number of people who tested negative for the disease; the probability of not having a condition, given a negative test
NEGATIVE PREDICTIVE VALUE
Dependent on the prevalence of a diseasel the higher the prevalence of a disease, the higher the positive aspect of the test
PREDICTIVE VALUE
Absence of vascular calcification in an adult suggests that severe valvular aortic stenosis is not present, meaning the valvular calcification is
SENSITIVE
one that is positive in most patient with the disease; if absence of a charateristic rules out a disease, then the test in sensitive, hardly anyone with the disease has a negative test
SENSITIVE TEST
In country A, there are 35 new cases of breast cancer per 100,000 adult women per year; in country B, the number is 90 per 100,000. What is the explanation?
WOMEN IN COUNTRY A ARE YOUNGER
Most important risk factor for the development of breast cancer, like most cancers
AGE
May have a protective effect on breast cancer but nowhere near the magnitude of the effect of age
NURSING
NOT a major risk factor for breast cancer
CIGARETTE SMOKING
Important cause of morbidity in Western world but mortality is decreasing; boys and girls are nearly equally affecter; most common in 2nd or 3rd decades of life; during pregnancy, displacement during pregnancy by the uterus may make diagnosis difficult
APPENDICITIS
Bacteria involved in nosocomial infections are transmitted most often via
DIRECT HAND CONTACT
Highly decrease transmission of nosocomial pathogens
METICULOUS HANDWASHING
Most common site of nosocomial infections
GENITOURINARY TRACT
Accounts for 35% of all nosocomial infections; 70-80% are related to catheters and urinary tract manipulations
UTI > SSI > RTI > SEPTICEMIA
Associated with acute episodes of asthma
EMOTIONAL STRESS, ELEVATED OZONE CONCENTRATIONS, URTI
Dust, animal dander, RTI’s, Ozone pollution, Aspirin, Emotional factors
TRIGGERS FOR ACUTE EPISODE OF ASTHMA
Methylxanthine related to Theophylline, a low- potency bronchodilator
CAFFEINE
Body fat of >30% of total body mass in Women, >25% in Men; major risk factor for DM2, relatively unimportant risk for CHD except at extremes of weight distribution; both behavioral and genetic factors contribute; arthritis is common; highly associated with Hypertension
OBESITY
most commonly caused by pernicious anemia in temperate climates sec to gastric mucosal atrophy sec to autoimmune reaction against parietal cells; increased risk in patients with a personal or family history of autoimmune disease; Diphyllobothrium latum, a fish tape worm; tropical sprue; RARELY with NONTROPICAL SPRUE
COBALAMIN (VITAMIN B12) DEFICIENCY